The present invention relates to a solution for prolonged organ preservation, and more particularly to an aqueous solution for organ preservation or maintenance. The invention also provides a method of preserving or maintaining an organ, comprising contacting the organ with the solution for organ preservation or maintenance.
Adequate preservation of organs intended for transplantation is critical to the proper functioning of the organ following implantation. This invention concerns an organ preservation or maintenance solution that can preserve organs intended for transplantation for periods of time that are longer than the currently best solution available. A longer preservation time is desired to enable cross-matching of donor and recipient to improve subsequent survival, as well as to allow for coast to coast and international transportation of organs to expand the donor and recipient pools. Experimental work for this invention has focused on the heart, but the organ preservation or maintenance solution of the subject invention may be used for other organs, and for tissues and cells, as well.
Many different organ preservation solutions have been designed, as investigators have sought to lengthen the time that an organ may remain extra-corporeally, as well as to maximize function of the organ following implantation. Several of the key solutions that have been used over the years include: 1) the Stanford University solution [see, e.g., Swanson, D. K., et al., Journal of Heart Transplantation, (1988), vol. 7, No. 6, pages 456-467 (mentions composition of the Stanford University solution)]; 2) a modified Collins solution [see, e.g., Maurer, E. J., et al., Transplantation Proceedings, (1990), vol. 22, No. 2, pages 548-550; Swanson, D. K., et al., supra (mention composition of modified Collins solution)]; and 3) the University of Wisconsin solution (Belzer, et al., U.S. Pat. No. 4,798,824, issued Jan. 17, 1989). Of those, the University of Wisconsin (UW) solution is currently regarded as the best. (See, e.g., Maurer, E. J., et al., supra).
In addition to the composition of the organ preservation or maintenance solution, the method of organ preservation also affects the success of preservation. Several methods of cardiac preservation have been studied in numerous publications: 1) warm arrest/cold ischemia; 2) cold arrest/macroperfusion; 3) cold arrest/microperfusion; and 4) cold arrest/cold ischemia. The first method involves arresting the heart with a warm cardioplegic solution prior to explantation and cold preservation, but this method fails because of the rapid depletion of myocardial energy store during the warm period. The second method, which involves arresting the heart with a cold preservation solution, is better; but continuous perfusion of the heart with preservation solution during the storage period fails because of the generation of toxic oxygen radicals. In addition, the procedure of the second method is cumbersome and does not lend itself to easy clinical use. The third method, first described in Nature in 1972 in a system called "trickle perfusion," is better but also cumbersome. The fourth method of preservation is that of a cold cardioplegic arrest followed by a period of cold immersion of the heart. The fourth method is currently the standard method of cardiac preservation. This fourth method reliably preserves hearts for periods of up to six (6) hours, but less than four (4) hours is considered ideal for this method. Since a longer preservation time is desirable, attempts have been made to improve preservation solutions in such a way as to reliably preserve hearts and other organs for longer periods of time.
Though the University of Wisconsin (UW) solution is currently the industry standard of organ preservation solutions, it is limited in the length of preservation time that it provides.